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Roman To Integer.py
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Roman To Integer.py
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#LeetCode - 13 : Given a roman numeral, convert it to an integer.
#using hashtable (Dictionary)
Time complexity – O(1)
Auxiliary Space – O(1)
```
class Solution:
def romanToInt(self, s: str) -> int:
dict = {'I' : 1,
'V' : 5,
'X' : 10,
'L' : 50,
'C' : 100,
'D' : 500,
'M' : 1000
}
l = len(s)
res = dict[s[l-1]]
for i in range(l-2,-1,-1):
if dict[s[i]] >= dict[s[i+1]]:
res += dict[s[i]]
else:
res -= dict[s[i]]
return res
```
#using .replace()
Time complexity – O(N)
Auxiliary Space – O(1)
```
class Solution:
def romanToInt(self, s: str) -> int:
dict = {'I' : 1,
'V' : 5,
'X' : 10,
'L' : 50,
'C' : 100,
'D' : 500,
'M' : 1000
}
res = 0
s = s.replace("IV", "IIII").replace("IX", "VIIII")
s = s.replace("XL", "XXXX").replace("XC", "LXXXX")
s = s.replace("CD", "CCCC").replace("CM", "DCCCC")
for char in s:
res += dict[char]
return res
```